U.S. patent application number 12/351544 was filed with the patent office on 2010-07-15 for hybrid powertrain and dual clutch transmission.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to Alan G. Holmes.
Application Number | 20100179024 12/351544 |
Document ID | / |
Family ID | 42319479 |
Filed Date | 2010-07-15 |
United States Patent
Application |
20100179024 |
Kind Code |
A1 |
Holmes; Alan G. |
July 15, 2010 |
HYBRID POWERTRAIN AND DUAL CLUTCH TRANSMISSION
Abstract
An automatic dual clutch transmission includes an input clutch
which selectively connects a prime mover to an electric motor. The
electric motor, in turn, is connected to the inputs of a pair of
coaxial friction clutches. Each of the coaxial outputs of the
friction clutches drives an input gear with meshes with a pair of
gears, one of which is associated with each of a respective pair of
layshafts or countershafts. On each countershaft, between the pair
of gears driven by the outputs of the two clutches, are a pair of
synchronizer clutches which selectively synchronize and connect one
of the two gears to the associated countershaft. A similar
arrangement of a second pair of gears separated by synchronizer
clutches connects the countershafts through a selected gear to a
pair of output gears coupled to and driving a differential cage or
spool.
Inventors: |
Holmes; Alan G.; (Clarkston,
MI) |
Correspondence
Address: |
VIVACQUA LAW, PLLC
455 East Eisenhower Parkway, Suite 200
ANN ARBOR
MI
48108
US
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
Detroit
MI
|
Family ID: |
42319479 |
Appl. No.: |
12/351544 |
Filed: |
January 9, 2009 |
Current U.S.
Class: |
477/5 ; 74/331;
903/917 |
Current CPC
Class: |
B60Y 2400/428 20130101;
F16H 48/08 20130101; F16H 2003/0931 20130101; Y02T 10/6221
20130101; B60K 6/36 20130101; Y10T 74/19233 20150115; Y02T 10/62
20130101; F16H 2200/0017 20130101; Y10T 74/19014 20150115; F16H
2200/006 20130101; Y10T 477/26 20150115; B60K 2006/541 20130101;
F16H 3/006 20130101; B60K 6/48 20130101 |
Class at
Publication: |
477/5 ; 74/331;
903/917 |
International
Class: |
F16H 3/093 20060101
F16H003/093; B60K 6/36 20071001 B60K006/36; B60K 6/38 20071001
B60K006/38 |
Claims
1. A dual clutch automatic transmission comprising, in combination,
a input clutch having an input adapted to be driven by an engine
and an output, an electric motor coupled to said output of said
input clutch, a pair of clutches having inputs coupled to said
electric motor and having a first clutch output and a second clutch
output, a first countershaft and a second countershaft spaced from
and parallel to said first countershaft a first gear coupled to
said first clutch output and in constant mesh with a first input
gear disposed on said first countershaft and a second input gear
disposed on said second countershaft, a second gear coupled to said
second clutch output and in constant mesh with a third input gear
disposed on said first countershaft and a fourth input gear
disposed on said second countershaft, a first synchronizer clutch
assembly disposed on said first countershaft between said first and
said third input gears for selectively connecting said gears to
said first countershaft, a second synchronizer clutch assembly
disposed on said second countershaft between said second and said
fourth input gears for selectively connecting said gears to said
second countershaft, a first output gear disposed on said first
countershaft and in constant mesh with a first differential input
gear, a second output gear disposed on said second countershaft and
in constant mesh with said first differential input gear, a third
output gear disposed on said first countershaft and in constant
mesh with a second differential input gear, a fourth output gear
disposed on said second countershaft and in constant mesh with a
said second differential input gear, a third synchronizer clutch
assembly disposed on said first countershaft between said first and
said third output gears for selectively connecting said gears to
said first countershaft, a fourth synchronizer clutch assembly
disposed on said second countershaft between said second and said
fourth output gears for selectively connecting said gears to said
second countershaft, and a differential assembly driven by said
first and said second differential gears and having a pair of
coaxial outputs.
2. The dual clutch transmission of claim 1 wherein said
synchronizer clutch assemblies between said input gears include two
synchronizer clutches.
3. The dual clutch transmission of claim 1 wherein said
synchronizer clutch assemblies between said output gears include a
single synchronizer clutch.
4. The dual clutch transmission of claim 1 wherein each of said
input and output gears is utilized with two forward gear
ratios.
5. The dual clutch transmission of claim 1 wherein said electric
motor is bi-directional and provides reverse.
6. The dual clutch transmission of claim 1 wherein said first input
gear is associated with third and seventh gears, said second input
gear is associated with first and fifth gears, said third input
gear is associated with fourth and eighth gears and said fourth
input gear is associated with second and sixth gears.
7. The dual clutch transmission of claim 1 wherein said first
output gear is associated with seventh and eighth gears, said
second output gear is associated with fifth and sixth gears, said
third output gear is associated with third and fourth gears and
said fourth output gear is associated with first and second
gears.
8. A dual clutch transmission comprising, in combination, a pair of
clutches having a common input and first and second outputs, a
first countershaft and a second countershaft spaced from and
parallel to said first countershaft a first gear coupled to said
first output and in constant mesh with a first input gear disposed
on said first countershaft and a second input gear disposed on said
second countershaft, a second gear coupled to said second output
and in constant mesh with a third input gear disposed on said first
countershaft and a fourth input gear disposed on said second
countershaft, a first synchronizer clutch assembly disposed on said
first countershaft between said first and said third input gears
for selectively connecting said gears to said first countershaft, a
second synchronizer clutch assembly disposed on said second
countershaft between said second and said fourth input gears for
selectively connecting said gears to said second countershaft, a
first output gear disposed on said first countershaft and in
constant mesh with a first differential input gear, a second output
gear disposed on said second countershaft and in constant mesh with
said first differential input gear, a third output gear disposed on
said first countershaft and in constant mesh with a second
differential input gear, a fourth output gear disposed on said
second countershaft and in constant mesh with a said second
differential input gear, a third synchronizer clutch assembly
disposed on said first countershaft between said first and said
third output gears for selectively connecting said gears to said
first countershaft, a fourth synchronizer clutch assembly disposed
on said second countershaft between said second and said fourth
output gears for selectively connecting said gears to said second
countershaft, and a differential assembly driven by said first and
said second differential gears and having a pair of coaxial
outputs.
9. The dual clutch transmission of claim 8 wherein said
synchronizer clutch assemblies disposed between said input gears
include two synchronizer clutches.
10. The dual clutch transmission of claim 8 wherein said
synchronizer clutch assemblies disposed between said output gears
include a single synchronizer clutch.
11. The dual clutch transmission of claim 8 wherein each of said
input and output gears is utilized with two forward gear
ratios.
12. The dual clutch transmission of claim 8 wherein said electric
motor is bi-directional and provides reverse.
13. The dual clutch transmission of claim 8 wherein said first
input gear is associated with third and seventh gears, said second
input gear is associated with first and fifth gears, said third
input gear is associated with fourth and eighth gears and said
fourth input gear is associated with second and sixth gears.
14. The dual clutch transmission of claim 8 wherein said first
output gear is associated with seventh and eighth gears, said
second output gear is associated with fifth and sixth gears, said
third output gear is associated with third and fourth gears and
said fourth output gear is associated with first and second
gears.
15. A dual clutch automatic transmission comprising, in
combination, a pair of clutches having a commonly driven input and
first and second independent outputs, a first countershaft and a
second countershaft, a first gear coupled to said first output and
in constant mesh with a first input gear disposed on said first
countershaft and a second input gear disposed on said second
countershaft, a second gear coupled to said second output and in
constant mesh with a third input gear disposed on said first
countershaft and a fourth input gear disposed on said second
countershaft, first synchronizer clutches disposed on said first
countershaft between said first and said third input gears for
selectively connecting said gears to said first countershaft,
second synchronizer clutches disposed on said second countershaft
between said second and said fourth input gears for selectively
connecting said gears to said second countershaft, a first output
gear disposed on said first countershaft and a second output gear
disposed on said second countershaft in constant mesh with a first
differential input gear, a third output gear disposed on said first
countershaft and a fourth output gear disposed on said second
countershaft in constant mesh with a second differential input
gear, a third synchronizer clutch disposed on said first
countershaft between said first and said third output gears for
selectively connecting said gears to said first countershaft, a
fourth synchronizer clutch disposed on said second countershaft
between said second and said fourth output gears for selectively
connecting said gears to said second countershaft, and a
differential assembly driven by said first and said second
differential input gears and having a pair of coaxial outputs.
16. The dual clutch transmission of claim 15 wherein each of said
input and output gears is utilized with two forward gear
ratios.
17. The dual clutch transmission of claim 15 wherein said electric
motor is bi-directional and provides reverse.
18. The dual clutch transmission of claim 15 wherein said first
input gear is associated with third and seventh gears, said second
input gear is associated with first and fifth gears, said third
input gear is associated with fourth and eighth gears and said
fourth input gears is associated with second and sixth gears.
19. The dual clutch transmission of claim 15 wherein said first
output gear is associated with seventh and eighth gears, said
second output gear is associated with fifth and sixth gears, said
third output gear is associated with third and fourth gears and
said fourth output gear is associated with first and second gears.
Description
FIELD
[0001] The present disclosure relates to a powertrain and
transmission for a motor vehicle and more particularly to a hybrid
powertrain and dual clutch transmission for a motor vehicle.
BACKGROUND
[0002] The statements in this section merely provide background
information related to the present disclosure and may or may not
constitute prior art.
[0003] Within the motor vehicle automatic transmission art, the
dual clutch transmission (DCT) is a relative newcomer. A typical
dual clutch transmission configuration includes a pair of mutually
exclusively operating input clutches which drive a pair of
layshafts or countershafts disposed on opposite sides of an output
shaft. One of each of a plurality of pairs of constantly meshing
gears which define the various forward gear ratios is freely
rotatably disposed on one of the layshafts and the other of each
pair of gears is coupled to the output shaft. A plurality of
synchronizer clutches selectively couple one of the gears to the
layshaft to achieve a forward gear ratio. After the synchronizer
clutch is engaged, the input clutch associated with the active
layshaft is engaged.
[0004] Dual clutch transmissions are known for their sporty,
performance oriented shift characteristics. They typically exhibit
good fuel economy due to good gear mesh efficiency and ratio
selection flexibility in design. The synchronizer clutches have low
spin losses which also contributes to overall operating
efficiency.
[0005] However, dual clutch transmissions have several unique
design considerations. For example, because of the torque
throughput during launch and the heat that can be generated during
slip, the input clutches must be of a relatively large size. The
size requirement applies as well to the cooling system which must
be able to dissipate relatively large quantities of heat. Finally,
because such transmissions typically have many sets of axially
aligned gears, their overall length may be problematic in some
platform configurations.
[0006] The present invention is directed not only to providing a
dual clutch automatic transmission have reduced axial length but
also to such a transmission for incorporation into a hybrid
powertrain.
SUMMARY
[0007] The present invention provides a dual clutch transmission
and differential having reduced axial length for incorporation into
a hybrid powertrain. The transmission is especially suited for
transverse installation in front wheel drive vehicles. The
transmission includes an input clutch which selectively connects a
prime mover such as a gas, Diesel of flexible fuel engine to an
electric motor. The input clutch may be disengaged when only
electric motor operation is desired. The electric motor, in turn,
is connected to the inputs of a pair of coaxial friction clutches.
Each of the coaxial outputs of the friction clutches drives an
input gear with meshes with a pair of gears one of which is
associated with each of a respective pair of layshafts or
countershafts. On each layshaft, between the pair of gears driven
by the outputs of the two clutches are a pair of synchronizer
clutches which selectively synchronize and connect one of the two
gears to the associated layshaft. A similar arrangement of a second
pair of gears flanked by synchronizer clutches connects the
layshaft through a selected gear to a pair of output gears coupled
to and driving a differential cage or spool. The outputs of the
differential are parallel to and spaced from the axis the clutches,
electric motor and input gears.
[0008] Thus it is an object of the present invention to provide a
dual clutch automatic transmission.
[0009] It is a further object of the present invention to provide a
dual clutch automatic transmission and electric drive motor.
[0010] It is a further object of the present invention to provide a
dual clutch automatic transmission for use in a hybrid
powertrain.
[0011] It is a further object of the present invention to provide a
dual clutch automatic transmission having an integral
differential.
[0012] It is a further object of the present invention to provide a
dual clutch automatic transmission having reduced axial length.
[0013] It is a further object of the present invention to provide a
dual clutch automatic transmission having an integral differential
and reduced length.
[0014] Further objects, advantages and areas of applicability will
become apparent from the description provided herein. It should be
understood that the description and specific examples are intended
for purposes of illustration only and are not intended to limit the
scope of the present disclosure.
DRAWINGS
[0015] The drawings described herein are for illustration purposes
only and are not intended to limit the scope of the present
disclosure in any way.
[0016] FIG. 1 is a schematic top plan view of a dual clutch
automatic transmission according to the present invention;
[0017] FIG. 2 is a schematic end elevational view of a dual clutch
automatic transmission according to the present invention;
[0018] FIGS. 3A and 3B are truth tables presenting the various
states of the two coaxial clutches and four synchronizer clutches
in the dual clutch transmission which achieve eight forward speeds
or gear ratios;
DETAILED DESCRIPTION
[0019] The following description is merely exemplary in nature and
is not intended to limit the present disclosure, application, or
uses.
[0020] With reference now to FIGS. 1 and 2, a dual clutch automatic
transmission according to the present invention is illustrated and
generally designated by the reference number 10. The automatic
transmission 10 includes a housing 12 which supports, receives and
protects the various components of the automatic transmission 10
such as an input shaft or member 14 which receives drive torque
from a prime mover such as a gasoline, Diesel or flexible fuel
engine (not illustrated) and connects to and drives a main or input
clutch 16. The main or input clutch 16 selectively engages to
provide drive torque from the prime mover to a main clutch output
shaft or member 18 which is coupled to an armature 22 of an
electric motor 20 and disengages to disconnect the prime mover from
the armature 22 of the electric motor 20. The electric motor 20 may
be an induction motor or more preferably a permanent magnet or DC
brushless motor. The electric motor 20 includes an output shaft or
member 24 which provides drive torque to a dual clutch assembly 30.
The dual clutch assembly 30 includes a common rotating housing or
drive member 31 driven by the output shaft 24 and includes two
coaxial single or multiple plate clutches and associated operators:
a first drive clutch 32 which selectively provides drive torque to
a first transmission drive shaft or member 34 and a second drive
clutch 36 which selectively provides drive torque to a second
transmission drive tube, quill or member 38 which is concentrically
disposed about the first transmission drive shaft or member 34.
[0021] The first transmission drive shaft or member 34 terminates
in a first drive gear 40 which is in constant mesh with a first
input gear 44 freely rotatable disposed upon a first (upper)
layshaft or countershaft 50 and a second input gear 52 freely
rotatably disposed upon a second (lower) layshaft or countershaft
60. The first input gear 44 is active when third and seventh gears
have been selected and the second input gear 52 is active when
first and fifth gears have been selected. The second transmission
drive tube, quill or member 38 terminates in a second drive gear 42
which is in constant mesh with a third input gear 46 which is
freely rotatably disposed on the first layshaft or countershaft 50
and spaced from the first input gear 44. A fourth input gear 54 is
freely rotatably disposed on the second layshaft or countershaft 60
and spaced from the second input gear 52. The third input gear 46
is active when fourth and eighth gears have been selected and the
fourth input gear 54 is active when second and sixth gears have
been selected.
[0022] Between the first input gear 44 and the third input gear 46
are a first pair of synchronizer clutches 48A and 48B. The first
pair of synchronizer clutches 48A and 48B are conventional and
operate to first synchronize and then positively connect the first
input gear 44 and the third input gear 46, respectively, to the
first layshaft or countershaft 50. Associated with the first pair
of synchronizer clutches 48A and 48B are a pair of operator and
shift fork assemblies 49A and 49B which axially and
bi-directionally translate the clutches 48A and 48B along the
layshaft or countershaft 50 and which may be either electric,
hydraulic or pneumatic. Likewise, between the second input gear 52
and the fourth input gear 54 are a pair of synchronizer clutches
58A and 58B. The second pair of synchronizer clutches 58A and 58B
are conventional and operate to first synchronize and then
positively connect the second input gear 52 and the fourth input
gear 54 respectively, to the second layshaft or countershaft 60. A
pair of electric, hydraulic or pneumatic operator and shift fork
assemblies 59A and 59B operate the second pair of synchronizer
clutches 58A and 58B.
[0023] A first output gear 62 is freely rotatably disposed on the
first layshaft or countershaft 50 adjacent the third input gear 46
and is in constant mesh with a third driven gear 82 secured to and
driving a cage or housing 84 of a differential assembly 90. A
second output gear 72 is freely rotatably disposed on the second
layshaft or countershaft 60 adjacent the fourth input gear 54 and
is also in constant mesh with the third driven gear 82. The first
output gear 62 is active when seventh and eighth gears have been
selected and the second output gear 72 is active when fifth and
sixth gears have been selected. A third output gear 64 is freely
rotatably disposed on the first layshaft or countershaft 50, spaced
from the first output gear 62 and in constant mesh with a fourth
driven gear 86 secured to and driving the cage or housing 84 of the
differential assembly 90. A fourth output gear 74 is freely
rotatably disposed on the second layshaft or countershaft 60,
spaced from the third output gear 64 and in constant mesh with the
fourth driven gear 86. The third output gear 64 is active when
third and fourth gears have been selected and the fourth output
gear 74 is active when first and second gears have been
selected.
[0024] Between the first output gear 62 and the third output gear
64 are a third pair of synchronizer clutches 66A and 66B. The third
pair of synchronizer clutches 66A and 66B is conventional and
operates to synchronize and connect the first output gear 62 and
the third output gear 64, respectively, to the first layshaft or
countershaft 50. One electric, hydraulic or pneumatic operator and
shift fork assembly 68 operates the third pair of synchronizer
clutches 66A and 66B. Likewise, between the second output gear 72
and the fourth input gear 74 are a fourth pair of synchronizer
clutches 76A and 76B. The fourth pair of synchronizer clutches 76A
and 76B is conventional and operate to synchronize and connect the
second output gear 72 and the fourth output gear 74, respectively,
to the second layshaft or countershaft 60. One electric, hydraulic
or pneumatic operator and shift fork assembly 78 operates the
fourth pair of synchronizer clutches 76A and 76B.
[0025] The differential assembly 90 and specifically the cage or
housing 84 is driven through either the first driven gear 82 or the
second driven gear 86, as noted. The differential assembly 90
includes four bevel gears (not illustrated) within the housing 84
disposed in pairs on two perpendicular axes and an opposed
(coaxial) pair of these bevel gears are coupled to and drive a
first output shaft 92 and a second, coaxial output shaft 94. The
output shafts 92 and 94 may be coupled to drive wheels through
universal joints (all not illustrated).
[0026] It should be understood that reverse gear may be provided by
a number of alternate means. For example, the main or input clutch
16 may be disengaged and the electric motor 20 may be energized to
rotate in reverse and drive through a low speed (high ratio) gear
such as first or second gear. Alternatively, an additional (idler)
gear and synchronizer clutch (not illustrated) may be incorporated
into the automatic transmission 10 to operate in conjunction with
for example, the gears 52 or 74 on the second countershaft 60.
[0027] FIGS. 3A and 3B are truth tables presenting two alternate
clutching schemes for the automatic transmission 10. An "X" in a
row for a particular speed or gear ratio indicates that the
actuator and countershaft clutch or the actuator and synchronizer
clutch associated with the gear indicated by the column heading are
activated and engaged. It should be noted that due to the shift and
clutching sequence of FIG. 3B, it is possible to utilize a single
synchronizer clutch operator 68A and 78A on the first countershaft
50 and the second countershaft 60, respectively, rather than
operate the pairs of synchronizer clutches 66A and 66B and 76A and
76B separately with the shift and clutching sequence of FIG. 3A due
to pre-staging or preselection requirements.
[0028] The foregoing description of the invention is merely
exemplary in nature and variations that do not depart from the gist
of the invention are intended to be within the scope of the
invention. Such variations are not to be regarded as a departure
from the spirit and scope of the invention and the following
claims.
* * * * *